ESRF Finds Oil in Cave Art

Photonics.comApr 2008
GRENOBLE, France, April 23, 2008 -- Light from the European Synchrotron Radiation Facility (ESRF) in Grenoble has proven that ancient paintings found in caves in Bamiyan, Afghanistan, were made with oil, hundreds of years before the technique was thought to have been invented in Europe.

The caves, decorated with paintings from the fifth to the ninth century, came to light in 2001 when the Taliban destroyed the two ancient, colossal Buddha statues in front of them. Although the caves also suffered from Taliban destruction, as well as from the severe natural environment, today they are shedding some light on an understudied research area -- paintings in Central Asia.Researchers take samples from the caves at Bamiyan, Afghanistan. (Image courtesy National Research Institute for Cultural Properties, Tokyo)
In many European history and art books, oil painting is said to have started in the 15th century in Europe. But scientists from the National Research Institute for Cultural Properties in Tokyo, the Centre of Research and Restoration of the French Museums-CNRS (France), the Getty Conservation Institute (US), and the ESRF have recently identified drying oils in some of the samples they studied from the Bamiyan caves.

Painted in the mid-seventh century, the murals show scenes with Buddhas in vermilion robes sitting cross-legged amid palm leaves and mythical creatures. The scientists discovered that 12 out of the 50 caves were painted with oil painting technique, using perhaps walnut and poppy seed drying oils.

A combination of synchrotron techniques such as infrared microspectroscopy, micro x-ray fluorescence, micro x-ray absorption spectroscopy or micro x-ray diffraction was crucial for the outcome of the work.
Close-up of a painting in the Bamiyan cave. (Image courtesy National Research Institute for Cultural Properties, Tokyo)
“On one hand, the paintings are arranged as superposition of multiple layers, which can be very thin. The micrometric beam provided by synchrotron sources was hence essential to analyze separately each of these layers. On the other hand, these paintings are made with inorganic pigments mixed in organic binders, so we needed different techniques to get the full picture,” said Marine Cotte, a research scientist at CNRS and an ESRF scientific collaborator. The world's largest statue of Buddha (174 ft high), shown in the Bamiyan Valley in Afghanistan in 1963. The statue was one of two destroyed by the Taliban in 2001, and behind which caves containing ancient oil paintings were found. (Image courtesy United Nations Educational, Scientific and Cultural Organization/A Lezine)
The results showed a high diversity of pigments as well as binders and the scientists identified original ingredients and alteration compounds. Apart from oil-based paint layers, some of the layers were made of natural resins, proteins, gums, and, in some cases, a resinous, varnish-like layer. Protein-based material can indicate the use of hide glue or egg. Within the various pigments, the scientists found a high use of lead whites. These lead carbonates were often used from antiquity to modern times, not only in paintings but also in cosmetics as face whiteners.

“This is the earliest clear example of oil paintings in the world, although drying oils were already used by ancient Romans and Egyptians, but only as medicines and cosmetics,” said Yoko Taniguchi, team leader.

The paintings are probably the work of artists who traveled on the Silk Road, the ancient trade route between China and the West, across Central Asia's desert. However, there are very few studies about this region. A cross-section of the sample, where the different layers are visible. (Image courtesy National Research Institute for Cultural Properties, Tokyo)
“Due to political reasons research on paintings in Central Asia is scarce. We were fortunate to get the opportunity from UNESCO (United Nations Educational, Scientific and Cultural Organization), as a part of conservation project for the World Heritage site Bamiyan, to study these samples and we hope that future research may provide deeper understanding of the painting techniques along the Silk Road and the Eurasian area,” Taniguchi said.

The results were presented in a scientific conference in Japan in January and appear this week in the Journal of Analytical Atomic Spectrometry.

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